Why do cosmological perturbations look classical to us

By Claus Kiefer, D. Polarski. 2008

210 citations recorded by the source corpus.

According to the inflationary scenario of cosmology, all structure in the Universe can be traced back to primordial fluctuations during an accelerated (inflationary) phase of the very early Universe. A conceptual problem arises due to the fact that the primordial fluctuations are quantum, while the standard scenario of structure formation deals with classical fluctuations. In this essay we present a concise summary of the physics describing the quantum-to-classical transition. We first discuss the observational indistinguishability between classical and quantum correlation functions in the closed system approach (pragmatic view). We then present the open system approach with environment-induced decoherence. We finally discuss the question of the fluctuations' entropy for which, in principle, the concrete mechanism leading to decoherence possesses observational relevance.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/a20aaa5206590e44d0e330bbde5c3f0cd31f68e0

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In Atomic and Molecular Physics, and Optics

In Statistical and Nonlinear Physics

Citations in the corpus

Models of Wave-function Collapse, Underlying Theories, and Experimental Tests (2012, background): “Decoherence accompanied by the many worlds interpretation has been proposed as one possible solution (Kiefer and Polarski, 2009).”